Water ingestion effects on gas turbine engine performance

摘要

Although gas turbine engines are designed to use dry air as the working fluid,the great demand over the last decades for air travel at several altitudes andspeeds has increased aircraft’s exposure to inclement weather conditions.Although, they are required to perform safely under the effect of variousmeteorological phenomena, in which air entering the engine contains water,several incidents have been reported to the aviation authorities about powerloss during flight at inclement weather. It was understood that the rain ingestioninto a gas turbine engine influences the performance of the engine andparticular the compressor and the combustor.The effects of water ingestion on gas turbine engines are aerodynamic,thermodynamic and mechanical. These effects occur simultaneously and affecteach other. Considering the above effects and the fact that they are timedependent,there are few gas turbine performance simulation tools, which takeinto account the water ingestion phenomenon.This study is a new research of investigating theoretically the water ingestioneffects on a gas turbine performance. It focuses on the aerodynamic andmechanical effects of the phenomenon on the compressor and the combustor.The application of Computational Fluid Dynamics (CFD) is the basicmethodology to examine the details of the flow in an axial compressor and howit is affected by the presence of water. The calculations of water film thickness,which is formed on the rotor blade, its motion (direction and speed) and theextra torque demand, are provided by a code created by the author usingFORTRAN programming language. Considering the change in blade’s profileand the wavy characteristics of the liquid film, the compressor’s performancedeterioration is calculated.The compressor and combustor’s deterioration data are imported to a gasturbine simulation code, which is upgraded to calculate overall engine’sperformance deterioration. The results show a considerable alteration inengine’s performance parameters and arrive at the same conclusions with therelevant experimental observations.